Image-guided inversion of electrical resistivity data

Zhou, Jun; Revil, A.; Karaoulis, M.; Hale, Dave; Doetsch, Joseph; Cuttler, Stephen W.

doi:10.1093/gji/ggu001

Cited by 96 publications

(50 citation statements)

References 31 publications

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“…Other cooperative inversion techniques, as used by Zhou et al (2014), apply smoothness weights at boundaries with dependence on a priori user-defined structures. That is, smaller weightings can be allocated proximal to the edge of faults or other potential geo-electrical boundaries.…”

Section: Other Methodsmentioning

confidence: 99%

Semiautomatic and Automatic Cooperative Inversion of Seismic and Magnetotelluric Data

Harris

Pethick

et al. 2016

Surv Geophys

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Natural source electromagnetic methods have the potential to recover rock property distributions from the surface to great depths. Unfortunately, results in complex 3D geo-electrical settings can be disappointing, especially where significant near-surface conductivity variations exist. In such settings, unconstrained inversion of magnetotelluric data is inexorably non-unique. We believe that: (1) correctly introduced information from seismic reflection can substantially improve MT inversion, (2) a cooperative inversion approach can be automated, and (3) massively parallel computing can make such a process viable. Nine inversion strategies including baseline unconstrained inversion and new automated/semiautomated cooperative inversion approaches are applied to industry-scale co-located 3D seismic and magnetotelluric data sets. These data sets were acquired in one of the Carlin gold deposit districts in north-central Nevada, USA. In our approach, seismic information feeds directly into the creation of sets of prior conductivity model and covariance coefficient distributions. We demonstrate how statistical analysis of the 123Surv Geophys (2016) 37:845-896 DOI 10.1007/s10712-016-9377-z distribution of selected seismic attributes can be used to automatically extract subvolumes that form the framework for prior model 3D conductivity distribution. Our cooperative inversion strategies result in detailed subsurface conductivity distributions that are consistent with seismic, electrical logs and geochemical analysis of cores. Such 3D conductivity distributions would be expected to provide clues to 3D velocity structures that could feed back into full seismic inversion for an iterative practical and truly cooperative inversion process. We anticipate that, with the aid of parallel computing, cooperative inversion of seismic and magnetotelluric data can be fully automated, and we hold confidence that significant and practical advances in this direction have been accomplished.

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Section: Other Methodsmentioning

confidence: 99%

Semiautomatic and Automatic Cooperative Inversion of Seismic and Magnetotelluric Data

Harris

Pethick

et al. 2016

Surv Geophys

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“…Constraints on ERI inversion can be deployed if drilling, wireline logging, and/or other geophysical data are available. In this case, joint, collaborative and cooperative inversion strategies can be deployed (e.g., Meju 2007, 2011; Le et al 2016;Marker et al 2015;Soueid Ahmed et al 2015;Takam Takougang et al 2015;Zhou et al 2014). We will provide field-based examples of how characterization of coastal aquifer systems can be advanced by integration of ERI with complementary data, such as ground penetrating radar (GPR).…”

Section: Figmentioning

confidence: 99%

Electrical Resistivity Imaging and the Saline Water Interface in High-Quality Coastal Aquifers

2018

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Population growth and changing climate continue to impact on the availability of natural resources. Urbanization of vulnerable coastal margins can place serious demands on shallow groundwater. Here, groundwater management requires definition of coastal hydrogeology, particularly the seawater interface. Electrical resistivity imaging (ERI) appears to be ideally suited for this purpose. We investigate challenges and drivers for successful electrical resistivity imaging with field and synthetic experiments. Two decades of seawater intrusion monitoring provide a basis for creating a geo-electrical model suitable for demonstrating the significance of acquisition and inversion parameters on resistivity imaging outcomes. A key observation is that resistivity imaging with combinations of electrode arrays that include dipole-dipole quadrupoles can be configured to illuminate consequential elements of coastal hydrogeology. We extend our analysis of ERI to include a diverse set of hydrogeological settings along more than 100 km of the coastal margin passing the city of Perth, Western Australia. Of particular importance are settings with: (1) a classic seawater wedge in an unconfined aquifer, (2) a shallow unconfined aquifer over an impermeable substrate, and (3) a shallow multi-tiered aquifer system over a conductive impermeable substrate. We also demonstrate a systematic increase in the landward extent of the seawater wedge at sites located progressively closer to the highly urbanized center of Perth. Based on field and synthetic ERI experiments from a broad range of hydrogeological settings, we tabulate current challenges and future directions for this technology. Our research contributes to resolving the globally significant challenge of managing seawater intrusion at vulnerable coastal margins.

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“…Here semi-automatic procedures can help to transform a guiding image into a form that can be used to steer a constrained inversion. Zhou et al (2014) have developed an image-guided inversion approach that uses such a transformation. Based on a guiding image, e.g., a GPR section, two quantities are calculated: (1) a metric tensor field that identifies directions of major changes and directions of homogeneity, the long axis of this tensor is aligned parallel to the direction where the reflection amplitudes are continuous, and (2) semblance, to identify the location of strong discontinuities, semblance values are low at major discontinuities.…”

Section: Cooperative and Constrained Inversionmentioning

confidence: 99%

“…Introducing the seismic constraint has made the models virtually independent of location c Fig. 15 Guiding image, calculated metric tensor field and semblance from that image as well as individual and constrained inversion results from the study of Zhou et al (2014). Introducing the structural constraints has increased the sharpness of several boundaries and changed the geometry of several structures to incorporate the tensor and semblance information in the inversion though, it is necessary to define a threshold below which the semblance is considered to indicate a boundary.…”

Section: Cooperative and Constrained Inversionmentioning

confidence: 99%

Integrating Electromagnetic Data with Other Geophysical Observations for Enhanced Imaging of the Earth: A Tutorial and Review

Moorkamp

2017

Surv Geophys

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In this review, I discuss the basic principles of joint inversion and constrained inversion approaches and show a few instructive examples of applications of these approaches in the literature. Starting with some basic definitions of the terms joint inversion and constrained inversion, I use a simple three-layered model as a tutorial example that demonstrates the general properties of joint inversion with different coupling methods. In particular, I investigate to which extent combining different geophysical methods can restrict the set of acceptable models and under which circumstances the results can be biased. Some ideas on how to identify such biased results and how negative results can be interpreted conclude the tutorial part. The case studies in the second part have been selected to highlight specific issues such as choosing an appropriate parameter relationship to couple seismic and electromagnetic data and demonstrate the most commonly used approaches, e.g., the cross-gradient constraint and direct parameter coupling. Throughout the discussion, I try to identify topics for future work. Overall, it appears that integrating electromagnetic data with other observations has reached a level of maturity and is starting to move away from fundamental proof-of-concept studies to answering questions about the structure of the subsurface. With a wide selection of coupling methods suited to different geological scenarios, integrated approaches can be applied on all scales and have the potential to deliver new answers to important geological questions.

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Image-guided inversion of electrical resistivity data

Cited by 96 publications

References 31 publications

Semiautomatic and Automatic Cooperative Inversion of Seismic and Magnetotelluric Data

Semiautomatic and Automatic Cooperative Inversion of Seismic and Magnetotelluric Data

Electrical Resistivity Imaging and the Saline Water Interface in High-Quality Coastal Aquifers

Integrating Electromagnetic Data with Other Geophysical Observations for Enhanced Imaging of the Earth: A Tutorial and Review

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